異世界二度目のおっさん、どう考えても高校生勇者より強い, Isekai Ni Dome No Ossan, Do Kangaete Mo Kokosei Yusha Yori Tsuyoi

Takayanagi Riku is a 32-year-old office worker with no particular characteristics. He actually has a special past in that he once saved another world as a hero, but now he lives in Japan as an ordinary office worker. But one day, he gets caught up in a group of three high school students and is summoned to another world again――!? Riku is confused by this sudden turn of events, but he encourages the high school heroes, who are even more confused than he is, and teaches them how to survive in another world... The second adventure of this caring and extremely strong old man begins in style!!